Steam boiler



K. C. SCHMIDT STEAM BOILER Filed April 15, 1935 4 sheet -sheet 1 INVENTOR Karl CSchmz'a f ATTORNEY Feb.22,1938; KQS'CHMIDT 211 STEAM BOILER Filed April 1935 v 4 Sheets- Sheet 21 f INVENTOR- ATTORNEY M, m Q Q Q Q 0 & 1f w 2 OOOOOOOOOOOOOOOOOOOOO0000000000 4 OOOOOOOOOOOOOOOOAWMWO000000000000 OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOO OOOOOOOOOOOOOOOOOO T RY wN m m M L 3 H m 1 C B u S M r A D. c m A s m K 1 i F 000 0000 o o oo oo oo oo oo oo oo oo oo\oo oo oo oo oo oo oo oo oo oo oo oo oo oo ofiw oo oo 00 0 0 00 oo o oo oo oo oo oo oo 00 0000 00 00 00 00 oo 00 o OOOO Feb. 22, 1938.

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Feb. 22, 1938. K c; sC 2,109,277

STEAM BOILER Filed April 13, 1955 4' Sheets-Sheet 4 o ,L,v\ w a I Q; {g

L, B INVENTOR.

Kari ckschmzdzf @R W ATTORNEY.

Patented Feb. 22, 1938 UNITED STATES PATENT OFFICE to The Babcock & Wilcox Company, N. 'J., a corporation of New Jersey Application April 13,

20Claims.

large amount of convection and radiant heat absorbing surface, furnace volume, length of heating gas travel and steam collecting space provided in proportion to the total space occupied and head room required, its relatively low cost of construction, and its ease of assembly and erection.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described preferred embodiments of my invention.

of the drawings:

Fig. 1 is a transverse vertical section of a steam boiler constructed in accordance with my invention taken on the line l--l of Fig. 2;

Fig, 2 is a longitudinal vertical section taken on the line 2-2 of Fig. 1;

Fig. 3 is a horizontal section taken on the line 3-3 of Fig. 2;

Fig. 4 is a partial longitudinal vertical section taken on the line 4-4 of Fig. 1;

Fig. 5 is a horizontal section through the dry drum taken on the line 55 of Fig. 1; and

Fig. 6 is a view similar to Fig. 1, illustrating a modification.

The steam boiler unit illustrated in Figs. 1 to 5 comprises a setting or housing substantially rectangular in horizontal and vertical cross-sections, and formed by a front wall It), rear wall ll, side walls l2 and ill, a top wall or roof I4, and bottom wall or floor I5. The side, end, and top walls are advantageously formed, as shown, by an outer steel casing [6, an inner layer of insulating material I1, and a fire brick lining I8. Extending upwardly along the side walls are I-beams l9 which support girders 20 extending across the top of the setting.

The interior of the setting is divided as hereinafter described into a relatively wide central combustion lane 2| and a pair of relatively nar- 55 row laterally adjoining heating lanes 22 at oppo- Newark,

1935, Serial No. 16,115

site sides thereof. A pair of horizontally disposed substantially parallel upper and lower drums 23 and 24 respectively extend longitudinally and throughout the length of eachheating lane and are connected throughout their length by a bank 5 of substantially'straight vertically disposed tubes 25 having bent ends radially connected into the drums at both sides of the vertical plane including the longitudinal axes of the drums. .The drums 23 and 24 are advantageously of small diameter to present the necessary amount of surface for the tube bank connections while minimizing the head groom requirements and weightof the drums. The upper drums 23 are supported from the girders 20 as indicated, and in turn support the lower drums 24 through the tube banks 25.

Each heating lane is separated from the ad joining combustion lane except at the rear end thereof by a vertically disposed refractory partition 26 which extends between the drums 23 and 24 and terminates at its rear end a substantial distance from the rear wall ll. Each drum 24 is protected along its lower inner section by a refractory curb 21 extending along the floor I5. 5 The space between the opposite side of each lower drum and the adjacent side wall is closed by refractory material, so that the gases in the heating lanes aresubstantially confined to the space therein between the drums 23 and 24. A heating gas outlet or stack connection 28 controlled by a damper 29 is provided at the front end of each heating lane. With this arrangement heating gases generated in the combustion lane will divide at the rear end thereof between the two heating lanes and flow forwardly therein between the drums to the outlets 28.

The steam boiler illustrated is especially de-. signed for the burning of a fluid fuel, such as oil, gas or pulverized fuel, in suspension. An oil burner 30 is conventionally shown as mounted in a bln'ner port 3| centrally formed in the front wall it) and arranged to discharge astream of fuel horizontally into and towards the rear end of the combustion lane. The front end of the. combustion lane is formed by a refractory faced ignition section having a flat refractory arch 32 and a pair of rearwardly flaring refractory side walls 33 to facilitate ignition of the entering fuel and to reflect and radiate heat towards the portion of the combustion lane at the rear thereof.

The portion of each tube bank laterally adjoining the ignition section of the combustion lane is utilized as an ecouomizer section. As

shown in Figs. 1 and 4, the three foremost rows of tubes 23 have their upper ends enclosed by a pan or box 34 to which feed water is supplied, and the lower drum 24 is divided by a partition into a short front compartment and a long rear compartment. With this arrangement the feed water will pass downwardly through the tubes communicating with the pan 34. and then upwardly through the remaining tubes in front of the drum partition 35. The feed water then distributes along the remaining portion of the tube bank, some of the tubes acting as downcomers and others as risers.

The section of the combustion lane between the rear end of the ignition section and the rear end of the partition 24 is normally the main combustion zone and is surrounded by radiant heat absorbing surface. As shown, oppositely arranged intersecting rows of substantially L- shaped water tubes 33 extend transversely of the combustion lane, each having one leg 33 connected to a corresponding lower drum and inclined across the bottom of the combustion lane and a second verticalleg 36" extending upwardly along and partly supporting the opposite partition 23' with the upper'end of the vertical leg connected into the opposite upper drum 23. The horizontally disposed legs of the two rows of tubes 33 intersect at approximately the middle of the bottom of the combustion lane, as shown in Fig. 1. The tubes in the two rows alternate, so that adjacent tube legs are substantially in contact at the plane of intersection, as shown in Fig. 2, and form. a water screen with progressively increasing vertical spacing between adjacent tube legs towards the sides of the combustion lane. The spaces along the inner sides of the partitions between the tube legs 36 are occupied by additional oppositely arranged alternating rows of L-shaped water tubes 31. Each 'of the tubes 31 has the lowerend of its vertical leg 31' connected to one of the drums 24 and extending upwardly along the corresponding partition 26 between the legs 33" of the tubes 33 and its second leg 31' extending at an inclination across the top of the combustion lane and connected to the opposite upper drum 23. The inclined legs 31' of adjacent tubes 31 intersect along approximately the middle of the combustion lane, and are arranged to support the top wall of the setting. The rowsof tubes 33 terminate at the rear end of the partition, but the row of tubes 31 on which theroofissupportedextendto therearwall II. as shown in Figs. 2 and 3. The tubes 38 and .31 are more closely spaced longitudinally than the tubes 23, but the spacing between adjacent tubes 31 is greater than between the tubes 23 so that the tube legs 31" beyond the rear end of the partition formin eifect a slag screen for the tubes 23 atthe rearend of the tube banks. By this arrangement of the combustion lane tubes 38 and 31, a fluid circulation is provided between the two pairs of drums and tube banks so that common pressure and water level conditions will be maintained in both sections of the boiler. Uniform operating conditions are further insured by an equalizer tube 33, as shown in Figs. 2 and 3, extending between the rear ends of the lower drums 24, and bent to accommodate any expansion stressesthat mayoccurin operation. An access door is provided at the floor level in the front wall In operation with this arrangement of the parts, most of the steam will be generated in the radiantheatabsorbingtubesfl and 31 andinthe rear section of the tube banks. A steam outlet connection 40 is provided at the front or economizer end of each drum 23 in view of the relatively quiescent conditions in that section. A splash plate 4|, having a rearwardly curved upper end extends across each drum 23 at the rear end of the economizer section to insure non-turbulent conditions in the economizer sections. A longitudinally extending perforated dry pipe 42 is located inthe economizer end of the drum above the water level therein and connected to the corresponding steam outlet 43.

A dry drum is arranged above and extending transversely of the forward ends of the drums 23, with its opposite ends connected to the steam outlets 40. The dry drum contains a relatively wide inclined channel plate II at each end thereof directly in the path of the wet steam from the outlet connections 40, causing the steam to change direction around the sidesof the channel and the moisture impinging on and adhering to the plate to drop into the bottom of the dry drum. The dry drum is provided with drain connections 52 leading to and sealed in the adjacent upper drum 23. The steam outlet 53 from the dry drum is advantageously arranged to extend horizontally from the upper central portion thereof to further reduce the head room requirements of the unit.

As shown in Fig. 4, a vertically extending Figs. 1 to 5 by the absence of the tube connections between the spaced tube banks and drums. In this construction, the tubes 36 and 31 of the combustion lane are ,replaced'by' two oppositely arranged rows of continuous 'U-shaped tubes 33, having oppositely inclined top and bottom legs and 80' respectively connected to upper and lower drums at the same side of the boiler and intermediate vertical legs 30 extending along the inner side of the opposite partition. The opposite rows of U-shaped tubes have their corresponding legs 30' and lfl intersecting along the vertical axial plane of the combustion lane. The between the vertical legs-'30 along the partitions 26 are occupied by vertically disposed tubes 3| extending between corresponding upper and lower While in accordance with the provisions of the statutes I have illustrated and described preferred embodiments of my invention, those skilled in the art will understand that changes may be made in the form of the apparatus disclosed without departing from the spirit of the invention covered by my claims, and that certain features 2 of my invention may sometimes be used to advantage without a corresponding use of other features.

I claim:

1. A steamboiler having a pair of substantially parallel horizontally disposed upper and lower drums, a bank of vertically disposed water tubes extending between and connected to said drums along the length thereof, means forming a longi- 2 tudinally extending combustion lane and aheating lane laterally adjoining said combustion lane and containing said tube bank, a row of substantially L-shaped water tubes extending transversely of said combustion lane each having one leg connected to, said lower drum and extending along the bottom of said combustion lane and the second leg along the side opposite said tube'bank, a second row of substantially L-shaped .water tubes extending transversely of said combustion lane each having one leg connected to said lower drum and extending along said tube bank and the second leg extending across the top side thereof, a longitudinally extending drum connectedto the upper ends or bothof said rows. of-L- shaped tubes, and means Ior burning fuel in said combustion lane andgenerating heating ,gases flowing longitudinallythereof and thence through said heating lane.

2. A steam boiler having a. pair of substantially parallel horizontally disposed upper and lower drums, a bank" 01' substantially straight vertically disposed water tubes extending between and connected tosaid drums'along the length thereof and disposed at both sides of the plane including the longitudinal axes of said drums, means forming a longitudinally extending combustion lane arranged i-substantially wholly at one side of said axial plane and a heating lane laterally adjoining said combustion lane and containing said tube bank, said heating lane 'receiving heating gases solely from and communi- -cating with said combustion lane only at one end each having one leg connected to said lowerdrum and extending along, said partition and the secondleg extending across the topside of said combustion lane, a longitudinally extending drum connected to the upper endsoi bothioi' said rows of 'L-shaped tubes, and means at the opposite end of said combustion lane for burning fuel therein and generating heating gases flowing longitudinally through :said' combustion lane and thence through said heating lane.

3. A steam boiler having a pairoi substantially parallel horizontally disposed upper and lower :drums, a. bank of vertically disposed water tubes extending between and connected to said drums along the length thereof, means forming a longitudinally extending combustion lane and a heating lane laterally adjoining said combustion lane and containing said tube bank and communicating with said combustion lane at one end thereof, said means including a vertically disposed longitudinally extending partition separating and forming one side of said combustion and heating lanes, a row of substantially L-shaped water tubes extending transversely of said combustion lane each having one leg connected tosaid lower drumand extending along the bottom oiLsaid combustion lane and the second leg along the side opposite said tube bank, a second row of sub stantially L-shaped water tubes extending transversely of said combustion lane each having one leg connected tosaid lower drum and extending along said partition and the second legextending across the top side of said combustion lane. a longitudinally extending drum connected to the pairsof substantiallyparallelhorizontally disposed upper and lower drums, a bank ,divertically disposed'water' tubes extending between and connected to each pair oi drums along the length thereof, means forming aflon gitudinally extending combustion 'laneand heating lanes laterally adjoining said combustion lane, each of said heating lanes containing one ots aid tube banks and communicating with said combustion lane at one end thereoiaoppositelyarranged intersecting rows oi' substantially L-shaped water tubes extendingtransversely oi said combustion 'lane each having one leg connectedto one of said lower drums and extendinglateralry along the bottomoi' said combustion lane and thesec- 0nd leg upwardly along the opposite'side thereof,

the upper end of each'oi's'aid L-shaped tubesbeing connected to the opposite upper drum, and means at the opposite end of saidcombustion lane for burning fuel therein and generating heating gases flowing longitudinally through said combustion lane andthence through said heating a lanes.

5. A steam boiler having horizontally spaced pairs oisubstantially parallel horizontallydlsposed upper and lower drums, a bank'of vertically disposed water tubes extending between and connectedto eachv pair of drums along the length, thereof, means forming a longitudinally extending combustion 'lane and heating lanes laterallyadjoining said combustion lane, each of said heating lanes containing oneof saidjtube banks and communicating with said combustion lane at one end thereohoppositely arranged intersecting rows of substantially L-shaped water I tubes extending transversely of saidflcombustion lane each having one .leg connected to one of said lower drums and extending'upwardly along the corresponding side of said combustion lane and the second leglaterally along, the root there-. of, the upper end or each of said vL-shaped tubes.

being connected to the opposite upper-drum, and

means at the opposite end of said combustion' lane ior burning fuel thereinfand generating heating gases flowing longitudinally through said combustion lane and thence throughsaid heating lanes. t I l l I V 8. A fsteam boiler having horizontally spaced pairsof substantially parallel horizontally disposed upper and lower drums, a. bank ot vertically disposed water tubes extendingbetween and connected to each pair of drums alongthe length i s thereof, means formingla longitudinally extending combustion, lane and heating lanes laterally adjoining; said combustion lane, feach; of said heating lanes containing one of said tube banks 1 and communicating with said combustion lane only at oneend thereof, said means including vertically disposed longitudinally extending partitions separating said combustion lane iromsaid heating lanes, oppositely arranged intersecting rowso! substantially L-shapedwater tubesextending transversely of saidcombustion lane beyond the end of said partitions and each having one leg connected to one of said lower and extendingupwardly along the corresponding side of saidcombustion lane and thesecond leg laterally along-and supporting the root of said 7 l combustion lane, the upper end oieach. of said L-sh'aped tubes being'connected to the opposite upper drum,'and means at the opposite end of said combustion lane for burning fuel therein and generating :gases iiowing longitudinally through said combustion lane and thence through said heating lanes.

as 'boiler having horizontally spaced i pairsoi substantially parallel'horizontally'disl" posed upper and lower drums, a bank oi vertically tubes'e'xtendingbetween and connected to each pair of drumsalong the length thereof, means forming a longitudinally "extendingcombustion lane and heating lanes laterally adioining 'said combustion lane, each I 61' said heating lanes containing one'oi said tube banks and communicatingj'with said combustion lane at one end thereof, opposltelyarranged inrows oi substantially L-shaped water tubes extending transversely of said combustion lane each havingone'leg connected to one or said lower drums and extending laterallyalong the bottom of said com'bustion lane and the second leg upwardly-along the opposite side thereof. additional oppositelyfarranged intersecting rows of substantially i.'-shaped 'water tubes" extending transversely'oi said combustion lane each having one leg connected to 7 one of said lower drums and extendlngu'pwardly along the corresponding side of said combustion lane and the second leg laterally along the root of-said'combustion'lane, the upper end of "eachof said L-shape'd tubes being connected to the opposite upper drum, and means at the oppositeend of said combustion lane for burning fuel therein and generating heating gases flowinglongltudinaiiy through said combustion lane and thence throughsaid heating lane's. I

, 8 A steamboiler having horizontallyspaced pairs of substantially parallel horizontally disposed upper and lower drums, abanlr oi yerti'caily' disposed water tubes extending between and to each pair of drums'along the length thereoi, means forming-a longitudinally extending combustion lane and "heating lanes laterally adjoining said combustion lane, each of said'heating lanes containing one of said tube :banks and communicating with said combustion laneonlyat ,end thereof, said means ineluding vertically longitudinally extend- 'ing partitions separating said combustion lane, from said heating lanes, oppositely arranged intersecting rows ofsubstantially L-shaped was ter tubes extending of 'saidcombus- I second leg upwardly along the, opposite side there.-

of. additional oppositely arranged intersecting rows of substantially -l.-shaped water'tubes extending transversely of said combustion lane each one leg connected to oneoi said lower and extendingupwardiyalong -the corpartition and the leg laterthe rector said the oi'each oI-said L-shaped tubes beopposite end of said combustion ioifuel therein and generating gases flowing lonsiuidinally through said 'laneand reversely through I ld heatv A pairsoi' substan lower drums, a: of subr drum ,"and' having spaced horizontally dis- I stantially straight vertically disposed water tubes extending betweenand connected to each pair of drums along the length thereof and disposed at both sides' oi the plane including thelongl-tudinai axes'otsaid drums, means forming a longi+ tudinally extending combustion lane and heating lanes laterally adjoining said combustion lane, each oisaid heating'lanescontaining one of said tube banks, said heating lanes receiving ,heating gases solelyirom and communicating with said combustion lane only'atone end thereof,

said means including vertically'disposed longltudin'ally extending partitions separating said combustion'lane from said heating lanes, oppositely arranged intersecting rows of substantially L-sha'ped water tubes extending I transversely oi said combustion lane each having one leg connected to one of said lower drums and extending laterally along the'bo'ttom of said com; bu'stion lane and the second'leg upwardly along the opposite side"thereoLfadditional oppositely arranged intersectinggrows oi substantially L- shaped water tubes- I extending transversely a or said combustion laneeach having one 11 81 9 11- 1 nected-to one 01'', said lower-"drums and extending upwardly along the corresponding partition,

and the second leg laterally along therooi" of said combustion lane, the upper .end of eachoi said L-shapedtubes being connectedto the op-.

positeupper' drum, and means at the opposite gitudlnally through saidfcombustion lane and reversely through 'said'heating lanes. 1

10. A steam boiler having horizontallyspaced so s end of said combustion lane iorfbuming 'i'uel therein and generating heating gases flowing ionpairs'of horizontally disposed upper-and lower drums, a bank of water tubes extending between and connected to each'pair oi" 'along'the 7 length thereoi', means. defining a combustion chamber between and extendinglongitudinally of saidtube banks, said means, includingv oppositely arranged rows 01' bent water, ,tubes extend- :ing transversely of said combustion chamber, each of saidbent tubes having onelegconnected to one of said lower drums and extending laterally across the lower "portion of'said combustion chamber and a second leggupwiardly along the upperfendof each of saidfbent tubes'being connected 'to one of said upper drums.

11. A steam boiler having horizontallyfspaced pairs ot horizontally disposed upperand lower drums, a bank of water tubes'extending tween and connected to each pair of drums along the length thereoi. means defining a combustion chamber between and extending longitudb nallyot' saidtube banks; said means including; oppositely arranged rows of substantially L-' shaped water tubes extending transversely of said combustion chambergeachoi said L-shaped, tubes'having one leg connected to one oi'-said ftheopposite side of saidcombustlon chamber;

lower drums and extending laterally acrossthe lower portion of saidcombustion chamber and" its second leg upwardly along the opposite side of said combustion chamber, the upper endof each of said L-shaped tubes being connected to the opposite upper drum. 12; A steam boiler having horizontally spaced pairs of'horizontally disposed upper and. lower drums, a bank oi'wat'er tubes extending between and connected to each pair of drums along the length thereof, means defining acombustion chamber between and extending longitudinally 01' said tube banks, said means including oppositely'arranged rows oi substantially L-shaped along opposite sides of said combustion lane,

water tubes extending transversely of said combustion chamber, each of said L-shaped tubes having an inclinedleg connected to one of said lower drums and extending laterally across the lower portion of said combustion'chamber and intersecting the axialplane of the inclined legs of the oppositely arranged L-shaped tubes and its second leg extending upwardly along the opposite side of said combustion chamber, the upper end of each of said L-shaped tubes being connected to the opposite upper drum, and means for burning fuel in suspension in said combustion chamber above said inclined tube legs.

13. A steam boilerhaving horizontally spaced pairs of substantially parallel horizontally disposedupper and lower drums, a bank of vertically disposed water tubes extending between and connected to each pair of drums along the length thereof, means forming a longitudinally extending combustion lane and heating lanes at opposite sides of said combustion lane, each of said heating lanes containing one or said tube banks and communicating with said combustion lane at one end thereof, oppositely arranged intersecting rows of bent water tubes extending transversely of said combustion lane, each of said bent tubes having one leg connected to one of said lower drums and extending laterally across the lower portion of said combustion lane and a second leg upwardly along the opposite side thereof and connected to one of said upper drums, and means at the opposite end of said combustion lane for burning fuel therein and, generating heating gases flowing longitudinally through said combustion lane and thence through said heating lanes.

14. A steam boiler having horizontally spaced pairs of horizontally disposed upper and lower drums, a bank of vertically disposed water tubes extending between and connected to each pair of drums along the length thereof, means defining a combustion chamber between and extending longitudinally of said tube banks, said means including oppositely arranged rows of bent water tubes extending transversely of said combustion chamber between upper and lower drums and including oppositely inclined tube legs connected to said lower drums and extending laterally across the lower portion of said combustion chamber, vertical tube legs extending upwardly along opposite sides of said combustion chamber, and oppositely inclined tube legs connected to said upper drums and extending laterally across the upper portion of said combustion chamber, and means for burning fuel in suspension in said combustion chamber.

15. A steam boiler having horizontally spaced pairs of substantially parallel horizontally disposed upper and lower drums, a bank of vertically disposed water tubes extending between and connected to each pair of drums along the length thereof, means forming a longitudinally extending combustion lane and heating lanes at opposite sides of said combustion lane, each of said heating lanes containing one of said tube banks communicating with said combustion lane at one end thereof, oppositely arranged rows of bent water tubes extending transversely of said combustion lane between upper and lower drums and including oppositely inclined tube legs connected to said lower drums and extending laterally across the lower portion of said combustion lane, vertical tube legs extending upwardly and oppositely inclined tube legs connected to said upper drums and extending laterally across the upper portion of said combustion lane, and means at the opposite end of said combustion lane for burning fuel therein'and generating heating gases longitudinally through said combustion lane.

16. A steam boiler having horizontally spaced water tubes extending transversely of said combustion chamber, eachof said L-shaped tubes having one leg connected to one of said lower a 20 drums and extendinglaterally across the lower portion of said combustion chamber and its second leg upwardly along the opposite side thereof, additional oppositely arranged rows of substantially -L-shaped water tubes extending transversely of said combustion chamber, each of said additional 'L-shaped tubes havingone leg connected to one of said lower drums and extending upwardly along the corresponding side of said combustion chamber and its second leg laterally across the upper portion of said combustion chamber, the upper end of each of said L-shaped tubes being' connected to the corresponding opposite upper drum. r

17. A steam boilerhaving horizontally spaced pairs of horizontally disposed upper and lower drums, a bank of vertically. disposed water tubes extending, between and connected to each pair of drums along the length thereof, means forming partitions separating a longitudinally extending combustion lane from heating lanes at opposite sides of said com bustion lane, each of said heating lanes containing one of said tube banks and opening to said combustion lane beyond one end of said partitions, oppositely arranged rows of substantially L-shaped water tubes extending transversely of said combustion lane beyond the end of said partitions and each having one leg connected to one of said lower drums and extending upwardly along the corresponding side of said combustion lane and spaced from adjacent L- shaped tubes to form a slag screen across the entrance to each of said heating lanes and its second leg extending across the upper portion of said combustion lane and connected to the opposite upper drum, and means for burning fuel in said combustion lane and generating heating gases flowing longitudinally through said combustion lane and thence through said heating lanes.

18. A steam boiler comprising a horizontally disposed upper drum, a substantially parallel laterally spaced lower drum, means defining a horizontally elongated combustion chamber in the space between and extending longitudinally of said drums, said means including oppositely ar ranged groups of substantially L-shaped' water tubes extending transversely of said combustion chamber, the L-shaped tubes in one of said groups having one leg connected to said lower drum and extending laterally across the lower portion of said combustion chamber and a second leg upwardly along the opposite side thereof, the L- shaped tubes in the other of said groups having one leg connected to said lower drum and extending upwardly alongthe corresponding side of said combustion chamber and a second leg laterally across the upper portion of said combustion chamber, the upper end of each of said L-shaped tubes being connected to said upper drum, "and means at one end oi said combustion chamber for burning fuel and generating a horizo'ntal flow of heating gases longitudinally, therethrough.

- 19. A steam. boiler comprising a horizontally disposed upper drum, a substantially parallel laterally spaced lower drum, means defining a horizontally elongated combustionchamber in the space between and extending longitudinally of said drums, said means including oppositely arranged rows of substantially L-shaped water tubes extending transversely of said combustion chamber, the L-shaped tubes in one of said'rows having one leg connected to said lower drum and extending laterally across the lower portion 01' said combustion chamber and a second leg upwardly along the opposite side thereof, the L- shaped tubes inthe other of said rows having one leg connected to said lower drum and ex-- tendingupwardly along the corresponding side oi said combustion chamber and its second leg laterally across the upper portion 0! said combustion chamber, the upper end of each of said L-shaped tubes being connected to said upper drum, a bank 0! steam generating tubes directly connected into said upper drum, means including a partition defining a heating lane containing said tube bank and separating the combustion chamber and heating lane, and means for burning fuel in said combustion chamber and through said heating lane. V KARL c. scmmr. 3

generating a horizontal flow of heating gases longitudinally therethrough and subsequently through said heating lane.

20. A steam boiler comprising a horizontally disposed upper drum, a; substantially parallel latzontally elongated combustion chamber in the space between and extending longitudinally 01' said drums, said means including oppositely arranged groups 01' substantially L-shaped' water tubes extending transversely of said combustion chamber, the L-shaped tubes inone of said groups having one leg connected to said lower drum and extending laterally across thelower portion 01' said combustion chamber and a second leg upwardly along the opposite side thereof, the L-shaped tubesin the other oi said groups having one leg connected to said lower drum and extending upwardly along the correspondim side of said combustion chamber and its second leg laterally across the upper portion 01' said combustion chamber, the upper end or each oi. said L-shaped tubes being connected to said upper drum, avertical bank of steamgenerating tubes directly connected into one ofsaid drums and arranged along one side 01' said combustion chamber, means including a vertical partitiondelining a heating lane containing,- said vertical.

erally'spaced lower drum, means defining a horltube bank and separating the combustionchamher and heating lane, and means at one end of said combustion chamber for burning fuel and generating a horizontal flowoi' heating gases longitudinally therethrough and subsequently 

